The speed of sound in standard seawater (diluted with pure water and evaporated) has been measured relative to pure water with a Nusonics single-transducer sound velocimeter as a function of salinity (5–40 o/oo), temperature 0°-40°C, and applied pressure (0–1000 bars). The effect of pressure on the relative speeds of sound, (Up-UpH20)-(Uo-UoH20), have been fitted to an equation of the form (with a standard deviation of 0.19 msec-1) (Up-upqhu0-UoH2O)=AS(0/oo) + BS(°/oo)^2+ CS(°/oo)2, where U and UH20arethe speeds of sound in seawater and pure water, respectively; superscripts P and O are used to denote applied pressure P and O (1 atm); A, B, and C are temperature-and pressure-dependent parameters; S(o/oo) is the salinity in parts per thousand. This equation has been combined with the refitted high-pressure pure-water sound-speed equation of Wilson [Naval Ordnance Lab. Rep. (1959)], Chen and Millero [J. Acoust. Soc. Am. 60, 1270–1273 (1976)], and the 1-atm seawater sound-speed data of Millero and Kubinski [J. Acoust. Soc. Am. 57, 312–319 (1975)] to calculate the speeds of sound for seawater at various salinities, temperatures, and pressures. Our results agree with the work of Wilson on the average to 0.36 msec-1over the range of 5 to 40 °/oo salinity, 0° to 3 °C, and 0 to 1000 bars. Over the oceanic range our results agree on the average with the work of Wilson to 0.3 msec-1(maximum deviation 0.6 msec-1), and with the work of Del Grosso to 0.5 msec-1(maximum deviation 0.9 msec-1). The better agreement of our results with those of Wilson may be fortuitous since our measurements were made relative to his pure-water data.
ASJC Scopus subject areas
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics